1. Field of the Invention
The present invention relates to a power supply management system in a parallel processing system by a multiprocessor and, more particularly, to a power supply management system in a parallel processing system by an OS for single processors capable of operating an OS and an existing application for single processors on a multiprocessor to enable the application to realize parallel processing by the multiprocessor.
2. Description of the Related Art
In data processing devices such as mobile terminals including a mobile phone and a mobile PC, an operating system for single processors (hereinafter referred to as an OS for single processors) and an application for single processors (hereinafter simply referred to as an application) are basically executed on a single processor.
Under these circumstances, when using the above-described application without modification on a multiprocessor basis, the application should be executed on an OS for multiprocessors in place of the above-described OS for single processors.
Among such systems which control execution of an OS for multiprocessors and an application on a multiprocessor system as described above are, for example, the conventional art disclosed in Japanese Patent Laying-Open (Kokai) No. Heisei 3-257652 and Japanese Patent Laying-Open (Kokai) No. Heisei 3-113563.
Japanese Patent Laying-Open (Kokai) No. Heisei 3-257652 (Literature 1) discloses a method of controlling interruptions between processor elements in a multiprocessor system composed of a plurality of processor elements.
Japanese Patent Laying-Open (Kokai) No. Heisei 3-113563 (Literature 2) discloses a method of scheduling processes to be assigned to a plurality of processors in a multiprocessor system.
On the other hand, Japanese Patent Laying-Open (Kokai) No. 2003-058515 (Literature 3) discloses a method of executing an individual process in a plurality of processor elements.
When operating an existing application on an OS for multiprocessors as in conventional art, however, the OS for multiprocessors provides services for multiprocessors even when the application uses only one among a plurality of processors, or continues processing mutually exclusive of other processors even when no other application operates, so that the extra processing causes overheads, or another problem might occur that modifying the above-described application so as to be used in multiprocessors requires enormous labor and costs.
In particular, when realizing a parallel processing system by a multiprocessor in small-sized data processing devices such as mobile terminals including a mobile phone and a mobile PC, overheads in processing of an OS for multiprocessors and modification of an application become hindrances.
Under these circumstances, when an application is used without modification on an existing OS for single processors, demanded is realization of a parallel processing system capable of operating an existing application on a multiprocessor.
Furthermore, when realizing a parallel processing system by a multiprocessor in small-sized data processing devices such as mobile terminals including a mobile phone and a mobile PC, power supply management is indispensable in order to reduce power consumption as much as possible.
In power supply management in a conventional parallel processing system by an OS for multiprocessors, because power supply management is conducted with a functionally symmetric power supply management unit provided in each processor, state of power supply of each processor needs to be seized and managed among all the processors. Therefore, when changing a state of power supply such as starting or stopping a specific processor, mutually exclusive control should be conducted among processors in order to maintain consistency in the system as a whole, resulting in making control complicated.
In such a system as operating an OS for single processors on each processor of a multiprocessor, application of complicated power supply management of a parallel processing system by an OS for multiprocessors requires drastic modification of the OS for single processors itself to involve labor and costs, while making execution of parallel processing by the multiprocessor meaningless because of extremely complicated control as bottleneck.
Among conventional art of conducting power supply management by a multiprocessor is a technique disclosed in U.S. Pat. No. 5,142,684 (Literature 4), for example. In the power supply management recited in Literature 4, with two kinds of processors whose processing speeds are different provided, a processor is selected according to processing to be executed and power necessary for the selected processor is controlled and supplied. The technique recited in Literature 4 is to conduct power supply control for two kinds of processors having different capabilities, which requires dedicated hardware and takes into consideration of none of such systems of operating an OS for single processors on each processor of a multiprocessor.